You had to get to those giant ant riders and pay them to travel. That's different.

I suppose that's a valid point, though with mark/recall you could easily avoid that risk, albeit with one extra step. Another reason I liked Oblivion's fast travel is that on my old machine, I would crash if I walked outside a city for more than 20 minutes.

I wouldn't say I was really "scared".. but knowing that you could get "startled" any moment gave you a certain feeling, whatever name you wanna tag on it.

At least in my case, I would feel that tension for maybe the first few surprises. Beyond that, I would realize I was in little danger of harm or death even at a subconscious level. Things jumping out from around the corner would still startle me now and then, but the anxiety and anticipation of that event was gone because my gun was always bigger.

in Splinter Cell Conviction you can: 1. Do stealthy kills; 2. Move silently and unseen; 3. Use stealthy gadgets; 4. Choose the renegade way and Rambo your way to the objective.If you'd ask me, I'd say that's the sum of a stealth/action game.

If you ask me, that's the sum of an action game with a stealth gimmick bolted on. If you can reasonably succeed at option 4, options 1-3 are superfluous and only serve to make the stealth-oriented player take twice as long to complete the same game. The core aspect of a stealth game is to be specifically unable to take all enemies head on. This is why I feel there is no such thing as a stealth/action game - the end goals and the means through which you achieve them are polar opposites. In an action game, you're supposed to be a match for every bad guy on the level combined, through a combination of better guns, better armor and intelligent use of cover and lame explosive objects or spike racks. In a stealth game, every single enemy should be a deadly threat, which is ok because you are supposed to be better at observing and exploiting the environment to bypass or defeat them. In simpler terms, your goal and means in an action game involve direct action, right in the enemy's face. In a stealth game, that should be the primary thing you are trying to avoid.

they could just aswell complain why in Mass Effect 2 you can't control the Normandy to blow up things ala Descent.

This isn't exactly a fair comparison. At least to my knowledge (I haven't played Mass Effect 2 yet) there are no points in Mass Effect 2 where you do directly control the Normandy. It would not make sense to do that, since it is a third person shooter and not a space sim. If they did add that in, it would probably be as gimmicky and second-rate as the Mako was.

By trying to make a stealth/action hybrid, they are just trying to simplify the game as a whole. The net effect is almost certainly going to be a poorer game in general. By sticking to the stealth roots of the series they can continue to have a unique game. Trying to give it wider appeal is going to invite comparison to other games that do stealth OR action better, and will ultimately make the game forgettable.